Method for providing a threaded fitting in a water tank header, header produced by the method and water tank including the header

ABSTRACT

A method for producing a header from a steel blank. The header has a boss and being of the type that is welded in use to a cylindrical wall to produce a hot water tank subassembly. The boss is interiorly threaded to define a threaded pressure vessel connection. The method includes the steps of extruding the boss in the steel blank and tapping the thread.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 61/734,115, filed Dec. 6, 2012, which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to a method for providing a threaded fitting in a water tank header, to a header produced by the foregoing method, and to a water tank including the header.

2. Related Art

The construction of water heaters typically involves the connection, by welding, of a pair of headers to a cylindrical wall, to form a tank. For the delivery of water into the tank, and the withdrawal of water therefrom, threaded pressure vessel connections are typically provided as part of the headers. The headers are typically each defined by a stamped body and, for each threaded fitting, a flanged threaded fitting which is welded to the body.

SUMMARY OF THE INVENTION

Forming one aspect of the invention is a method for producing a header from a steel blank, the header having a boss and being of the type that is welded in use to a cylindrical wall to produce a tank subassembly, the boss being interiorly threaded to define a threaded pressure vessel connection, the method comprising the steps of: extruding the boss in the steel blank; and tapping the thread.

According to another aspect of the invention, the extrusion of the boss can be carried out with an extrusion punch and extrusion die.

According to another aspect of the invention, the extrusion can involve passage of the extrusion punch through a preformed hole in the blank into the extrusion die.

According to another aspect of the invention, the extrusion punch can be about a 0.960″ extrusion punch, the preformed hole can be about a 5/16″ hole and the steel blank can be about 0.135″ thickness HRPO draw quality steel.

According to another aspect of the invention, the extrusion punch can be a 0.960″ extrusion punch, the preformed hole can be a 5/16″ hole and the steel blank can be a 0.135″ thickness HRPO draw quality steel.

According to another aspect of the invention, the extrusion punch can travel at about 480 inches per minute as the boss is formed.

According to another aspect of the invention, the extrusion punch can have a TD coating.

According to another aspect of the invention, the extrusion punch can be lubricated with Syndraw 99 lubricant.

A header produced according to the inventive method forms another aspect of the invention.

Forming yet another aspect of the invention is an improved water heater. The water heater is of the type comprising: a cylindrical wall and a pair of headers welded to the wall to form a tank; and a heating element coupled to the tank and adapted to heat the contents thereof. The improvement comprises: a header member, produced according to the inventive method, defining at least one of the pair of headers.

Other advantages, features and characteristics of the present invention will become more apparent upon consideration of the following detailed description of an exemplary embodiment of the invention and the appended claims with reference to the accompanying drawings, the latter being briefly described hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a prior art water heater tank;

FIG. 2 is a perspective view of an extrusion punch used in the exemplary embodiment of the invention;

FIG. 3 is an end view of the structure of FIG. 2;

FIG. 4 is a side view of the structure of FIG. 2;

FIG. 5 is a view along 5-5 of FIG. 3;

FIG. 6 is a perspective view of an extrusion die used in the exemplary embodiment;

FIG. 7 is an end view of the structure of FIG. 6;

FIG. 8 is a side view of the structure of FIG. 6;

FIG. 9 is a view along section 9-9 of FIG. 7; and

FIG. 10 is a view similar to FIG. 1 showing the construction of a water heater according to the exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A method for producing a header according to an exemplary embodiment of the invention is described hereinafter in detail.

However, as an initial manner, reference is made to FIG. 1, which shows a prior art water tank 11. Herein, it will be seen that the tank 11 is defined by a cylindrical wall 12 to which top 13 and bottom 14 headers are welded. Each of the top header 13 and bottom header 14 has a main body 15 having a plurality of landings 16 extending therefrom. The landings 16 in the bottom header 14 serve as feet for the tank 11. Some of the landings 16 in the top header 13 have threaded fittings 17 welded thereto. Each threaded fitting 17 is defined by a flange 18 welded to the landing 16 and a tubular part 19 extending from the flange 18 and in which threads are defined. Each main body 15 is a stamped component produced from 0.135″ HRP draw quality steel.

The method allows, inter alia, for threaded fittings to be provided on a water tank top header without the need for welding. This avoids, for example, weld splatter, as well as the need for an inventory of separate fittings, with commensurate impacts upon costs.

In the method, a blank of 0.135″ HRP draw quality steel is stamped in a conventional manner to form a dish (not shown) generally in the form of the prior art main body top header, but differing in that 5/16″ holes are provided in the landings that, in the prior art, would have had threaded fitting flanges secured thereto.

Thereafter, a 0.960″ extrusion punch, provided with a TD coating, is passed through each hole into a mating die to produce a boss. FIGS. 2 through 5 show the construction of a suitable punch; FIGS. 6 through 9 show the construction of a suitable die.

To avoid tearing, the punch is lubricated with Syndraw 99 lubricant and passed through the hole at about 480 inch/minute or less.

Thereafter, a ¾ NPT tap (not shown) is used to cut interior threads in each boss.

FIG. 10 is a cross-section similar to FIG. 1 but showing the results of the above method in a completed tank 20. Herein, it will be seen that the tank 20 includes the cylindrical wall 12 and bottom header 14 of the prior art, as well as a modified top header 13′ which includes a generally conventional main body 15 but, instead of welded threaded fittings, has a plurality of threaded bosses 22 extending from the landings 16.

Whereas a single embodiment is herein described, it will be evident that modifications can be made. Accordingly, the invention should be understood as limited only by the accompanying claims, purposively construed. 

What is claimed is:
 1. A method for producing a header from a steel blank, the header having a boss and being of the type that is welded in use to a cylindrical wall to produce a hot water tank subassembly, the boss being interiorly threaded to define a threaded pressure vessel connection, the method comprising the steps of: extruding the boss in the steel blank; and tapping the thread.
 2. The method according to claim 1, wherein the extrusion of the boss is carried out with an extrusion punch and extrusion die.
 3. The method according to claim 2, wherein the extrusion involves passage of the extrusion punch through a preformed hole into the extrusion die.
 4. The method according to claim 3, wherein the extrusion punch is about a 0.960 inch extrusion punch, the preformed hole is about a 5/16″ hole and the steel blank is about 0.135″ thickness HRPO draw quality steel.
 5. The method according to claim 3, wherein the extrusion punch is a 0.960 inch extrusion punch, the preformed hole is a 5/16″ hole and the steel blank is a 0.135″ thickness HRPO draw quality steel.
 6. The method according to claim 4, wherein the extrusion punch travels at about 480 inch/minute as the boss is formed.
 7. The method according to claim 5, wherein the extrusion punch travels at about 480 inch/minute as the boss is formed.
 8. The method according to claim 4, wherein the extrusion punch has a TD coating.
 9. The method according to claim 5, wherein the extrusion punch has a TD coating.
 10. The method according to claim 6, wherein the extrusion punch has a TD coating.
 11. The method according to claim 4, wherein the extrusion punch is lubricated with Syndraw 99 lubricant.
 12. The method according to claim 5, wherein the extrusion punch is lubricated with Syndraw 99 lubricant.
 13. The method according to claim 6, wherein the extrusion punch is lubricated with Syndraw 99 lubricant.
 14. The method according to claim 7, wherein the extrusion punch is lubricated with Syndraw 99 lubricant.
 15. The method according to claim 8, wherein the extrusion punch is lubricated with Syndraw 99 lubricant.
 16. A header produced according to claim
 1. 17. A header produced according to claim
 2. 18. A header produced according to claim
 3. 19. A header produced according to claim
 4. 20. An improved water heater of the type comprising: a cylindrical wall and a pair of headers welded to the wall to form a tank; and a heating element coupled to the tank and adapted to heat the contents thereof, wherein the improvement comprises: a member according to claim 16 defining at least one of the pair of headers. 